1、Designation: D732 10D732 17Standard Test Method forShear Strength of Plastics by Punch Tool1This standard is issued under the fixed designation D732; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*Scope1.1 This test method covers the procedure for deter
3、mining the shear strength of composite materials plastics in the form ofsheets, plates, and molded shapes in thicknesses from 1.27 to 12.7 mm (0.050 to 0.500 in.).1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 This s
4、tandard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.NOTE 1There is no known ISO
5、 equivalent to this standard.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organiza
6、tion Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD4000 Classification System for Specifying Plastic MaterialsD5947 Test Methods for Physical Dimensions of Solid Plastics SpecimensE4 Practices for Force Veri
7、fication of Testing MachinesE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 shear strengththe maximum load required to shear the specimen in such a manner that the moving portion of the loadfixture has completely cl
8、eared the stationary portion, divided by the sheared area. It is expressed in megapascalsmega-pascals (orpounds-force per square inch) based on the area of the sheared edge or edges.4. Significance and Use4.1 Shear strength obtained by the use of punch-type tooling is one of the recognized methods o
9、f comparing materials, orobtaining data for engineering design purposes, or both. However, it must be recognized that for end-use applications there arelikely to be many factors not taken into account in this test method, such as stress-concentrating geometries and rates of shear,which can profoundl
10、y affect the measured shear strength. Moreover, the fact that the shear strength is calculated by dividing theload by the area of the sheared edge (punch circumference X specimen thickness) does not interpret as indicating the shear strengthvalue so obtained is solely a material property, independen
11、t of thickness.4.2 For many materials, it is possible that there is a specification that requires the use of this test method, but with someprocedural modifications that take precedence when adhering to the specification. Therefore, it is advisable to refer to that materialspecification before using
12、 this test method. Table 1 of Classification System D4000 lists the ASTM materials standards thatcurrently exist.1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved Ap
13、ril 1, 2010May 1, 2017. Published April 2010June 2017. Originally approved in 1943. Last previous edition approved in 20092010 asD732 09.D732 10. DOI: 10.1520/D0732-10.10.1520/D0732-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm
14、.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
15、it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears
16、at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Apparatus5.1 Testing MachineAny suitable testing machine of the constant-rate-of-crosshead movement type. The testing machine shallbe equipped with the nece
17、ssary drive mechanism for imparting to the crosshead a uniform, controlled velocity with respect to thebase. The testing machine shall also be equipped with a load-indicating mechanism capable of showing the total compressive loadcarried by the test specimen. This mechanism shall be essentially free
18、 from inertia-lag at the specified rate of testing and shallindicate the load with an accuracy of 61 % of the indicated value or better. The accuracy of the testing machine shall be verifiedin accordance with Practices E4.5.2 Shear ToolA shear tool of the punch type which is so constructed that the
19、specimen is rigidly clamped both to thestationary block and movable block so that it cannot be deflected during the test. A suitable form of shear tool is shown in Fig.1.5.3 MicrometersSuitable micrometers Apparatus for measuring the thickness of the test specimen to an incrementaldiscrimination of
20、at leastshall comply with the requirements of Test Methods D59470.025 mm (0.001 in.)6. Test Specimen6.1 The specimen shall consist of a 50-mm (2-in.) square or a 50-mm50.8-mm (2-in.) diameter disk cut from sheet material ormolded into this form. The thickness of the specimen is limited from 1.27 and
21、 12.7 mm (0.050 and 0.500 in.). The upper and lowersurfaces shall be parallel to each other and reasonably flat. A hole approximately 11 mm (716 in.) in diameter shall be drilledthrough the specimen at its center.6.2 A minimum of five specimens of each sample material shall be tested. If fewer than
22、five specimens are tested, the reportshall reflect that results are based on a modified version of the standard.NOTE 1In case of difficulty in obtaining hardened dowels and bushings, the entire shear tool may be made from a fairly good grade of steel,eliminating all of the bushings shown. The actual
23、 working surfaces will wear faster than when hardened tool steel is used. When they show signs ofappreciable wear, the shear tool can then be bored out to take either hardened or unhardened bushings, depending upon which are available.FIG. 1 Punch-Type Shear Tool for Testing Specimens 0.127 to 12.7
24、mm (0.050 to 0.500 in.) in ThicknessD732 1727. Conditioning7.1 Pre-Test ConditioningCondition the test specimens in accordance with Procedure A of Practice D618 unless otherwisespecified by contract or the relevant ASTM material specification. Conditioning time is specified as a minimum. Temperature
25、 andhumidity tolerances shall be in accordance with Section 7 of Practice D618 unless specified differently by contract or materialspecification.7.2 Test ConditionsConduct the tests at the same temperature and humidity used for conditioning with tolerances inaccordance with Section 7 of Practice D61
26、8 unless otherwise specified by contract or the relevant ASTM material specification.8. Procedure8.1 Measure the thickness of each test specimen to the nearest 0.025 mm (0.001 in.) at a minimum of three points on a circleapproximately 12.7 mm (0.500 in.) from its center. Average the readings and rec
27、ord as the specimen thickness.8.2 Place the specimen over the 9.5-mm (38-in.) threaded pin of the punch and fasten it in place by securing the washer andnut tightly.8.3 Center the specimen and punch on the support fixture and complete the assembly of the clamping fixture being sure totighten the bol
28、ts securely.8.4 Load the test specimen at a crosshead speed of 1.251.27 mm (0.05 in.)/min. The tolerances shall be 1.3 6 0.3 mm (0.0506 0.010 in.)/min.8.5 Push the punch far enough through the specimen so that the sheared section clears the specimen proper. The specimen willthen be adjacent to the n
29、ecked-down portion of the punch, and it can then be readily removed from the tool.NOTE 2For thick specimens of some materials the punched-out piece tends to stick in the die. If the test is continued only to the point where maximumload has been developed and starts to fall off rapidly, the specimen
30、may be readily removed from both punch and die.9. Calculation9.1 Calculate shear strength in megapascals, mega pascals, MPa, (or pounds-force per square inch, psi), determined by dividingthe load required to shear the specimen by the area of the sheared edge, which shall be taken as the product of t
31、he thickness ofthe specimen by the circumference of the punch.10. Report10.1 Report the following information:10.1.1 Complete identification of the material tested, including type, source, manufacturers code number, form, principaldimensions, previous history, etc.,10.1.2 Method of test, type of tes
32、t specimen, and dimensions,10.1.3 Atmospheric conditions in the test room,10.1.4 Conditioning procedure used,10.1.5 Diameter of punch,10.1.6 Load in newtons (or pounds-force) required to shear each specimen, and the average value, and10.1.7 Shear strength in megapascals (or pounds-force per square i
33、nch) for each specimen, the average value, and the standarddeviation.11. Precision and Bias311.1 Table 1 is based on a round-robin test conducted in 1983, in accordance with Practice E691, involving six materials testedby eleven laboratories. Each “test result” was the average of five individual det
34、erminations. Each laboratory obtained one test resultfor each material. (WarningThe following explanations of r and R (11.2 11.2.3) are intended only to present a meaningful wayof considering the approximate precision of these test methods. The data given in Table 1 should not be applied rigorously
35、to theacceptance or rejection of materials, as those data are specific to the round robin and may not be representative of other lots,conditions, materials, or laboratories. Users of this test method should apply the principles outlined in Practice E691 to generatedata specific to their laboratory a
36、nd materials, or between specific laboratories. The principles of 11.2 11.2.3 would then be validfor such data.)NOTE 3Caution:The following explanations of r and R (11.2 11.2.3) are intended only to present a meaningful way of considering the approximateprecision of these test methods. The data give
37、n in Table 1 should not be applied rigorously to the acceptance or rejection of materials, as those data arespecific to the round robin and may not be representative of other lots, conditions, materials, or laboratories. Users of this test method should apply theprinciples outlined in Practice E691
38、to generate data specific to their laboratory and materials, or between specific laboratories. The principles of 11.2 11.2.3 would then be valid for such data.3 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D20-1120.D732 17311
39、.2 Concept of r and R in Table 1If Sr and SR have been calculated from a large enough body of data, and for test resultsthat were averages from testing five specimens for each test result, then:11.2.1 RepeatabilityTwo test results obtained within one laboratory shall be judged not equivalent if they
40、 differ by more thanthe r value for that material. The r value is the interval representing the critical difference between two test results for the samematerial, obtained by the same operator using the same equipment on the same day in the same laboratory.11.2.2 ReproducibilityTwo test results obta
41、ined by different laboratories shall be judged not equivalent if they differ by morethan the R value for that material. The R value is the interval representing the critical difference between two test results for thesame material, obtained by different operators using different equipment in differe
42、nt laboratories.11.2.3 The judgments in 11.2.1 and 11.2.2 will have an approximately 95 % (0.95) probability of being correct.11.3 BiasIt is not possible to make any statement about the bias of this test method, as there is no standard reference materialor reference test method that is applicable.12
43、. Keywords12.1 punch tool; shear strengthTABLE 1 Shear StrengthMaterialAValues Expressed in Units of Pound-Force per Square InchAverageThickness, in. Mean SrB SRC rD RERIM 0.134 2 900 32 155 92 439HDPE 0.071 3 410 27 135 76 382Polyester 0.128 8 580 57 278 163 788SMC 0.210 14 700 304 569 862 1 610Pol
44、yesterFPCTFEF0.01040.007610 2007 9003845281 9502 7301 0801 4905 5307 740TABLE 1 Shear StrengthMaterialAValues Expressed in Units of Pound-Force per Square InchAverageThickness, in. Mean SrB SRC rD RERIM 0.134 2900 32 155 92 439HDPE 0.071 3410 27 135 76 382Polyester 0.128 8580 57 278 163 788SMC 0.210
45、 14 700 304 569 862 1610PolyesterF 0.0104 10 200 384 1950 1080 5530PCTFEF 0.0076 7900 528 2730 1490 7740A The complete designations for the materials in Table 1 are: reaction injection molding (RIM), high-density polyethylene (HDPE), sheet molding compound (SMC), andpolychlorotrifluoroethylene (PCTF
46、E).BSr is the within-laboratory standard deviation for the indicated material. It is obtained by pooling the within-laboratory standard deviations of the test results from all ofthe participating laboratories: Sr5ff sS1d21sS2d2 1sSnd2g/ng1/2.CSR is the between-laboratory reproducibility, expressed a
47、s standard deviation: SR5hSr21SL2 j1/2 where SL is the standard deviation of laboratory means.Dr is the within-laboratory critical interval between two test results = 2.8 Sr.ER is the between-laboratory critical interval between two test results = 2.8 SR.F Values for 0.010 in. thick polyester specim
48、ens and 0.007 in. thick PCTFE specimens are included in Table 1 to show that the repeatability and reproducibility of shearstrength values were greatly inferior to corresponding data obtained on specimens of 1.780 mm (0.070 in.) minimum thickness. Therefore, the scope of this test methodwas revised
49、to limit test specimen thickness to the range from 1.27 to 12.7 mm (0.050 to 0.500 in.).D732 174SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue (D732 - 09)that may impact the use of this standard. (April 1, 2010)(1) Removed ASTM D4066 from 2.1.(2) Revised Section 7.Committee D20 has identified the location of selected changes to this standard since the last issue (D732 - 02)that may impact the use of this standard. (October 15, 2009)(1) Revised Sections: 1.1, 3.1.1, 4.1, 7.1,
